Process for slitting sheet metal

ABSTRACT

A process and apparatus for slitting sheet metal having a plurality of inflatable fluid passageways therein into strips, each having at least one inflatable fluid passageway which comprises providing sheet metal having at least two sheets pressure welded together in some areas and having a plurality of unwelded areas corresponding to inflatable passageways. The sheet metal contains at least one unwelded area extending within it in a predetermined fixed relationship to the remaining unwelded area, this one unwelded area being a control tube for use in aligning the sheet metal for slitting. The aligning of the sheet metal is achieved by passing it about a locater mandrel which plows open the control tube and fixes the position of the sheet as it enters the slitting assembly. The sheet metal as thus aligned then proceeds into a conventional slitting assembly wherein it is cut into strips. The locater mandrel may be fixed or may be provided with means for adjusting its position relative to the slitting assembly. A second slitting assembly may be employed ahead of the locater mandrel whose purpose is to remove a portion of the strip containing part of the control tube.

United States Patent [151 3,706,246

Keith [45] Dec. 19, 1972 [54] PROCESS FOR SLITTING SHEET 57 ABSTRACT METAL [72] Inventor: Norval A. Keith, East Alton, 111.

[73] Assignee: Olin Corporation, New Haven,

Conn.

[22] Filed: July 26, 1971 [21] Appl. No.: 166,268

Related U.S. Application Data [62] Division of Ser. No. 5,548, Jan. 26, 1970.

[52] U.S. Cl. "83/7, 29/470.9, 29/480, 29/481, ,83/9, 83/56, 83/418, 83/440 [51] Int. Cl. ..B26d 3/08 [58] Field of Search ..29/470.9, 475, 480, 481; 83/367,14, 418, 7, 9, 56, 440

[56] References Cited UNITED STATES PATENTS 3,045,330 7/1962 Johnson et al. ..29/470.9 X

3,121,950 2/1964 Maier et a1 ..29/470.9

3,368,261 2/1968 Pauls ..29/480 X 3,394,446 7/1968 Valyi ..29/470.9 X

Primary ExaminerJ. Spencer Overholser Assistant Examiner-Richard Bernard Lazarus Attorney-Robert H. Bachman A process and apparatus for slitting sheet metal having a plurality of inflatable fluid passageways therein into strips, each having at least one inflatable fluid passageway which comprises providing sheet metal having at least two sheets pressure welded together in some areas and having a plurality of unwelded areas corresponding to inflatable passageways. The sheet metal contains at least one unwelded area extending within it in a predetermined fixed relationship to the remaining unwelded area, this one unwelded area being a control tube for use in aligning the sheet metal for slitting. The aligning of the sheet metal is achieved by passing it about a locater mandrel which plows open the control tube and fixes the position of the sheet as itenters the slitting assembly. The sheet metal as thus aligned then proceeds into a conventional slitting assembly wherein it is cut into strips. The locater mandrel may be fixed or may be provided with means for adjusting its position relative to the slitting assembly. A second slitting assembly may be employed ahead of the locater mandrel whose purpose is to remove a portion of the strip containing part of the control tube.

5 Claims, 14 Drawing Figures PATENTED m 19 m2 SHEET 1 BF 2 NORl/AL A. KEITH INVENTOR ATTO RN EY PATENTED ntc 19 I972 A 5 I [JG-5 NORVAL A. KEITH v INVENTOR 25 BY I ATTORNEY PROCESS FOR SLITTING SHEET METAL This application is a division of copending application Ser. No. 5,548, filed Jan. 26, 1970.

In the manufacture of sheet metal tubing from continuous strip having inflatable fluid passageways, it is most economical to produce the material in a wide coil form which can later be slit into strips of the desired width. It is extremely difficult to slit this type of coil without cutting into one or more of the tube patterns. This is the case since the patterns must be close together from the standpoint of economy. The distance between the respective tube patterns and the edge of the coil is not consistent enough to enable one to use the edge of the coil as a slitting reference surface. Accuracy in the range of 0.005 to 0.010 inch is necessary when slitting this type of coil. The tube pattern edge to slit edge dimensional tolerances are not obtainable when using the prior art techniques which use the edge of the coil as a reference surface.

This invention has been devised to obtain the desired accuracy by providing a control tube pattern in the coil for guiding purposes. The dummy or control tube pattern is located in the coil in a fixed relationship to the other tube patterns so the coil can be accurately aligned with the slitter to cut the individual strips from it. In order to maintain the desired accuracy during slitting, in accordance with this invention, a locater mandrel is so designed that as the coil passes about it, the control tube is slit and plowed open, thereby providing the desired alignment of the coil as it enters the slitting assembly. The mandrel is stationary, as are the slitter knives, thus the coil is moved to align it with the slitter knives.

In the past, slitting of coils of the type useful with this invention, was accomplished by guiding them using their edges as the reference surface. This cannot produce the desired accuracy because the edge of the coil does not necessarily accurately follow the tubular patterns within the coil. The instant invention avoids this problem by patterning a control tube simultaneously with the working tube pattern so that an accurately fixed relationship is always maintained for reference during slitting.

It is accordingly an object of this invention to provide an apparatus for slitting sheet metal coilshaving a plurality of patterns of uninflated fluid passageways into strips, each having at least one inflatable fluid passageway.

It is a further object of this invention to provide an apparatus for slitting these coils in an accurate manner which will avoid cutting into the tubular patterns within each strip.

It is a further object of this invention to provide a sheet metal coil comprising at least two sheets of metal bonded together in some areas and having other areas forming patterns of inflatable fluid passageways and further including a control tube for reference during slitting.

It is a further object of this invention to provide a process for accurately slitting a sheet metal coil having a plurality of patterns of uninflated fluid passageways, into a plurality of strips each of which contains at least one inflatable passageway.

Other objects and advantages will become apparent from the following description and drawings, in which:

FIG. 1 shows a perspective view of a portion of a sheet metal coil in accordance with this invention.

FIG. 2 shows an edge view of a coil as in FIG. 1.

FIG. 3 shows an edge view of an inflated strip.

FIG. 4 shows a perspective view of one embodiment of an apparatus in accordance with this invention.

FIG. 5 shows a front view of an apparatus as in FIG. 4.

FIGS. 6A and 6B show the front and side views of a locater mandrel in accordance with this invention.

FIG. 7 shows a perspective view of a locater mandrel in accordance with this invention.

FIG. 8 shows a view of a'locater mandrel in plowing contact with a coil.

FIG. 9 shows a partial edge view of the coil in accordance with this invention immediately after passing the locater mandrel of FIG. 7.

FIG. 10 shows a perspective view of a preferred apparatus' in accordance with this invention.

FIG. 11 shows a perspective view of a preferred locater mandrel for use in the preferred apparatus in FlG. l0.

FIG. 12 shows a partial edge view of the coil immediately after passing the locater mandrel of FIG. 11.

FIG. 13 shows a perspective view of a pressure roller useful with the apparatus of FIG. 10.

Referring now to the drawings and especially to FIG. 1, there is illustrated a portion of a coil 1 exemplary of the type of coiled sheet useful in this invention. The coiled sheet with which this invention may be used may be fabricated by the method disclosed in US. Pat. No. 2,690,002 granted to Grenell on Sept. 28, 1954. For example, referring to FIG. 1, a pattern of weld inhibiting or stop-weld material 2 is applied to a clean surface of a sheet of metal 3. The stop-weld pattern 2 comprises a plurality of individual patterns laid out in longitudinally extending strip areas 4. It further includes at least one control tube pattern 5 extending longitudinally in the sheet and which is in a fixed relationship to the other patterns 2. This control tube pattern 5 provides the reference line for slitting. The other pattern of stop-weld 2 provide the inflatable fluid passageways in the strip which is slit from the sheet metal coil. A second sheet 6 of metal having a clean surface is superimposed on the surface of the first sheet 3 having the stop-weld pattern, and the two sheets 3 and 6 are secured together to prevent relative motion therebetween. Thereafter, the two superimposed sheets 3 and 6 are pressure welded together by rolling, so that the adjacent areas 7 of the sheets 3 and 6 which are not separated by stop-weld 2 and 5 become bonded together. The rolling of the sheets 3 and 6 results in reducing their thickness and in elongating the resultant sheet 1 in the direction of rolling. The width of the resultant sheet 1 remains substantially the same as the initial width of the sheets 3 and 6. Following the rolling operation, the resultant sheet 1 is usually softened as by annealing to make it more pliable. If desired, it may be further rolled to the final gage and again softened as by annealing.

The stop-weld material 2 and 5 results in the retention of unwelded portions 8, as shown in FIG. 2, corresponding to the stop-weld pattern 2 and 5 which is sandwiched between the outer surfaces of the resultant sheet 1. After softening this sheet and slitting it into strips 9, and unjoined portions are usually expanded as in FIG. 3 to form the desired passageways 10. This expansion is obtained by injecting a fluid, such as air or water, into the unjoined portions 8 under a pressure of sufficient magnitude, to permanently deform the sheet metal in that area so as to form the passageways 10.

It is to be understood, however, that other methods may be employed in the manufacture of the strips 9 used with this invention. For convenience in shipping and packaging, the resulting sheet 1 having the plurality of patterns 2 and 5. is put in coil form, however, the invention is applicable to sheets 1 of varying lengths whether coiled or flat.

As noted above, the coil in accordance with the instant invention contains a plurality of stopweld patterns 2 each of which lies within a longitudinal strip area 4 of the sheet metal 1. It is the object of this invention to slit the coil into strips 9 corresponding to the areas 4.In practice, the stop-weld patterns 2 for each strip area may be separated from each other by about 0.050 to 0.100 inch so that a slitting tolerance of 0.005 to 0.010 inch is desired though not obtainable by previous techniques. Although the stop-weld patterns may be laid out initially in accurate alignment with the edge of the sheet metal 1, the rolling operation required for bonding as above noted tends to distort this relationship. Thus, there is the necessity for the high tolerance noted.

It has been found that in use, a control tube pattern 5, one-fourth inch to five-eighth inch in width is practical and that the tolerance of the pattern 5 as deposited should be in the range of: 0.002 inch and preferably i 0.001 inch. The strips 9 which are cut from the sheet metal 1 normally vary from three-fourths inch in width to as much as 3 to 6 inches. A width of 1% inch is often used in practice.

Referring now to FIG. 4, there is shown an apparatus in accordance with this invention. The apparatus comprises a frame to which is mounted a slitting as sembly 21. The slitting assembly 21 comprises rotating slitting knives 22 which are arranged as shown in FIG. 5 to cut the sheet metal 1 into strips 9 of the desired width. The knives 22 are powered by means ofa motor, not shown. The apparatus also includes means for holding a sheet metal coil 23 and for supplying sheet metal 1 to the slitting knives 22 and a locater mandrel 24 which is in fixed spacial relationship to the slitting knives 22. As the sheet metal 1 from the coil is fed past the locater mandrel 24, the control tube 5 is plowed open, thereby accurately fixing the alignment of the sheet metal 1 as it passes into the slitting assembly 21.

As the sheet passes through the slitting assembly 21,

the portion with the control tube 5 is cut off and discarded as scrap and the remainder of the coil is cut into strips 9. The strips 9 each contain at least one stopweld pattern and again coiled, (not shown), for further processing.

The shape of the locater mandrel 24 is extremely important in this invention. Referring to FIGS. 6A and 68, there is shown a typical locater mandrel 24 for use in the apparatus shown in FIG. 4 wherein the control tube 5 is to be fully plowed out. The mandrel 24 has a flat bottom 25 whose width is within about 0.002 inch of the width of the control tube 5. There are inclined portions 26 emanating from opposite edges of the bottom 25 and which meet at 27 to form the plowing surface. The inclined portions are more readily discernable from FIG. 7 which shows the overall shape of the mandrel 24. As shown in FIG. 7, there are four inclined faces A, B, C and D in the inclined portion 26. The front two A and B are angled with respect to each other, so that they meet along line 27 and provide plowing action when the mandrel 24 engages the control tube 5. The side faces C and D provide the guiding function for the mandrel 24 as they accurately ride within the control tube 5. The mandrel also includes a shaft portion 28 which has sides 29 and faces E and F forming V" shaped front portion 30. The V" shaped front portion 30 functions to cut open the top sheet 6 of the control tube 5 so that the shaft portion 28 may pass through the control tube, while the inclined portion 26 rides within the control tube, plowing it open.

This is best shown in FIG. 8 where the'mandrel 24 is shown after the V" shaped portion 30 of the shaft 28 has cut the top sheet 6 of the control tube 5 apart. As shown, the bottom portion 25 of the mandrel 24 accurately fixed the alignment of the sheet 1 by substantially taking up the control tube 5 area. The inclined faces A and B of the mandrel 24 plow up the top sheet 6 and raise it out of the way, and after it is cut-by the V" shaped portion 30, the mandrel may pass on in a continuous fashion. Therefore, the sheet 1 is aligned with the mandrel 24 through the contact between the bottom sheet 3 and the bottom 25 of the mandrel and that between the cut apart top sheet 6 and the inclined portions C and D of the mandrel.

Referring again to FIG. 7, the mandrel 24 also includes a mounting portion 31 which has holes 32 through which the locating bolts, (not shown), are placed to secure the mandrel 24 to the apparatus, shown in FIG. 4. The cutting surface of the mandrel may be curved as shown in FIG. 6A to enhance the plowing action and render the cutting easier.

FIG. 9 shows the sheet 1 after it has passed the mandrel 24 but before it has entered the slitting assembly 21. It can be seen that the control tube 5 is cut open at the top sheet 6 and that the top sheet is plowed apart by the plowing action of the mandrel 24.

While the apparatus in accordance with FIG. 4 provides the accurately alignment desired with this inven tion, there may be tool wear of the locater mandrel 24 because it functions to both plow the tube 5 and to cut it open. Therefore, a preferred apparatus has been developed wherein a portion of the control tube is first slit off the sheet 1 and then the sheet 1 is fed past a locater mandrel which merely plows apart the top sheet 6 of the remaining portion of the tube 5. A suitable apparatus for carrying out this embodiment is shown in FIG. 10 and comprises a frame 101 and a first slitting assembly 102. The first slitting assembly is essentially similar to that described with reference to FIG. 4 and will not be discussed further. In this apparatus, there is a second slitting assembly 103 spaced ahead of the first slitting assembly 102 and ahead of the mandrel 100. This second slitting assembly 103 cuts off a portion of the control tube 5, usually about one-half its width. The sheet 1 then proceeds to the locater mandrel 100 which plows apart the sheets 3 and 6 of the control tube 5 as shown in FIG. 12. In order to provide for guiding the sheet 1, a pressure plate 104 or a roller assembly 105 as shown in FIG. 13, is used to maintain pressure against the edge 106 of the strip 1 so that it is pushed against'the locater mandrel 100. The pressure must be sufficient to push a strip against the locater mandrel with sufficient force so that the mandrel 100 presses into the edge of the control tube 5 pattern until the edge of the mandrel substantially reaches the edge of the control tube 5.

The locater mandrel used in this apparatus is essentially similar to the one shown in FIG. 4 and a typical one is shown in FIG. 11. The essential difference between it and the locater mandrel as shown in FIGS. 6 and 7 is that the bottom portion and inclined portions are essentially one-half of those in the other mandrel.

This apparatus also includes means 110 for adjusting the position of the locater mandrel 100. The locater mandrel 100 is mounted to a movable member 111 which rides in a key way 112 with accurate movement of the member being obrained by means of a micrometer drive 113. Screw 109 locks the mandrel in position. This means 110 for moving the mandrel may also be incorporated in the apparatus of FIG. 4.

The sheet 1 is presses against the mandrel 100 by means of a spring biased plate assembly 104 which is connected to the frame 101. The plate 114 exerts sufficient force by means of the spring 115 so that the control tube 5 as it passes the mandrel 100, is plowed open to substantially the limit of the unbonded portion 5.

FIG. 12 shows the sheet 1 afterpassing the mandrel 100 but prior to slitting. It is seen from this figure that the control tube of which about one-half remains, is plowed open up to the limit of the stop-weld pattern 5. The force exerted by the spring biased plate assembly 104 must be sufficient so that the mandrel 100 is plowing open the control tube 5 substantially up to the stopweld limit.

Alternatively, other means of applying pressure to the sheet 1 could be used, for example, in FIG. 13, there is shown a spring biased roller assembly 105 which engages the edge 106 of the sheet 1 to provide the requisite pressure. The roller 116 is mounted to a top plate 117 which is slidably mounted 118 to the frame. A spring 119 connected to the top plate 117 provides the pressure. Two pins 120 positioned within slots 121 in the top plate 117 provide for the sliding movement of the top plate 117.

In operation then, the sheet 1 is fed from the coil to the second slitting assembly 103 which cuts off about one-half of the control tube 5 and from there is passes about the locater mandrel 100 which plows open the control tube aligning the sheet 1 as it proceeds into the first slitting assembly which cuts the sheet 1 into the desired strips 9. The slitting rates may be substantially the same as those employed in conventional slitting operations.

While the locater mandrel has been described with respect to the embodiments shown in FIGS. 7 and 11, other shapes may be utilized with this invention. It isessential that the mandrel fill out in some manner the control tube so as to provide accurate alignment. In the embodiments of FIGS. 7 and 11, the flat bottom and inclined portions provide this function. It is also possible to employ locater mandrels having cylindrical shapes instead of the flat bottom 25 and inclined portions 26. The cylindrical shapes may be either of circular cross section or elliptical cross section. The front portion of the cylinder would be tapered in a conical ai t'li'. illif l fllhilfihlfvlilgllllfi sila 'flllfi be somewhat different to those previously described in that the bottom sheet 5 would also be deformed. ln essence, the circular or elliptical cross section would correspond to the shape of the control tube had it been inflated. The advantages of this type of too] over that disclosed with reference to FIGS. 7 and 11 is that it decreases the possibility of digging into the bottom sheet 5. Mandrels employing the cylindrical type plowing surface could still utilize the same type of shaft portion 28 and mounting portion 24 as disclosed with reference to FIG. 7.

It has also been found that as the lead end section of the mandrel corresponding to faces A and B in FIG. 7 is increased in length, the tendency to gaul or dig into the bottom sheet 5 is reduced.

The processes described above are applicable to any type of sheet metal which can be formed into the compositesheet described herein, and especially to aluminum and aluminum alloys, copper, copper alloys and steel. The strip 1 may be inflated as shown in FIG. 3 utilizing conventional inflating pressures which generally vary over a range of p.s.i. up to 3,000 p.s.|.

It is to be understood that the invention is not limited to theillustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are suitable of modification of form, size, arrangement of parts and details of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined by the claims.

What is claimed is:

l. A process of slitting sheet metal having a plurality of inflatable fluid passageways therein into stripseach having at least one inflatable fluid passageway, comprising:

providing sheet metal comprising at least two sheets of metal bonded together in some areas and having a plurality of unwelded areas corresponding to inflatable fluid passageways, said sheet metal containing at least one unwelded area extending within it in a predetermined fixed relationship to the remaining unwelded areas, said at least one unwelded area being a control tube for use in aligning said sheet metal for slitting;

passing said sheet metal about a locater mandrel so that said mandrel plows open the control tube and aligns said sheet metal for slitting; and

slitting said aligned sheet metal into a plurality of strips, with each strip containing at least one inflatable fluid passageway.

2. A process as in claim 1 wherein each strip contains a plurality of inflatable fluid passageways.

3. A process as in claim 1 wherein prior to passing said sheet metal about said mandrel, a portion of said control tube is removed.

4. A process as in claim 3 wherein each strip contains a plurality of inflatable fluid passageways.

5. A process as in claim 3 wherein pressure is applied to said sheet of metal as it passes about said locater mandrel so that the mandrel plows open the control tube substantially up the the limit of its unwelded area. 

1. A process of slitting sheet metal having a plurality of inflatable fluid passageways therein into strips each having at least one inflatable fluid passageway, comprising: providing sheet metal comprising at least two sheets of metal bonded together in some areas and having a plurality of unwelded areas corresponding to inflatable fluid passageways, said sheet metal containing at least one unwelded area extending within it in a predetermined fixed relationship to the remaining unwelded areas, said at least one unwelded area being a control tube for use in aligning said sheet metal for slitting; passing said sheet metal about a locater mandrel so that said mandrel plows open the control tube and aligns said sheet metal for slitting; and slitting said aligned sheet metal into a plurality of strips, with each strip containing at least one inflatable fluid passageway.
 2. A process as in claim 1 wherein each strip contains a plurality of inflatable fluid passageways.
 3. A process as in claim 1 wherein prior to passing said sheet metal about said mandrel, a portion of said control tube is removed.
 4. A process as in claim 3 wherein each strip contains a plurality of inflatable fluid passageways.
 5. A process as in claim 3 wherein pressure is applied to said sheet of metal as it passes about said locater mandrel so that the mandrel plows open the control tube substantially up the the limit of its unwelded area. 